Feed grinder



April 1,1930. c, AMMQN ET AL FEED GRINDER Filed Jan. 29, 1929 C.D.Ammon E WWilcox IN V EN TORS ATTORNEY Patented Apr. 1, 1930 UNITEDTST'ATES PATENT, OFFICE CHARLES. D. AMMON AND ELMER W. WILCOX, OF LINCOLN, NEBRASKA; SAID WILCOX ASSIGNOR '10 SAID AMMON I FEED GRINDER 7 Application filed January 29,1929. Serial No. 385,918.

1 5 The primary object of our invention is the provision of means whereby the screen will be securely latched in place in the mill and whereby it may be conveniently and easily inserted in the mill or-withdrawn therefrom -1 or replaced by another screen.

Another object of our invention is to provide a yielding pressure foot for the door of the feed opening so as to hold the door'in position under the vibration of the machine.

Having in view these objects and others which will be pointed out in the following description, we will now refer to the drawings, in which 1 Figure 1 is a median vertical sectional view of the entire feed grinder and showing specifically the screen in itslatched position and showing also the pressure foot .bearing against the closure. Figure 2 is a vertical sectional view I througha port-ion of the back wall of the feed grinder showing the rear connection 0 the screen with the back wall. p

Figure 3 is a view similar to "Figure 2 but showing the relationship of parts at the forward extremity of the screen in its relation to the front wall and to the screen opening when the screen is being forced into posi-.

tion.

Figure 4 is a view in front'elevation of the closure for the screen opening of the'feed grinder. I

' The feed grinder shown in our drawings is of the hammermill type with a shaft 10 adapted for a speed of about 3000 R. P. M. Secured to this shaft are pivoted hammers 11 which extend in radial direction when the grinder is in operation. The casing is providedwith a front opening 12 through which the feed is introduced. The feed coming through the opening 1 2 falls against the hammers 11 which crush the feed in mid air due to'the rapid movement of the hammers 11. The crushed and partly crushed feed is hurled against the anvils 13' and 13" and against the screen 14;. The impact of the partly crushed feedagainst the anvils results in a further crushing of the feed and this crushing process is repeated between the hammers 11 and the anvil '13 until the feed has been reduced tothe proper size. When the particles are sufiiciently fine they are hurled out through the screen 14c from whence they fall to the bottom of the casing where they may be removed.

In the operation of-feed grinders of this type it is frequently necessary to replace screens. This necessity arises from the fact that the grinder is used largely on farms where many different kinds of feed are ground ranging all the way from cornstalks to small grains. This, of course, necessitates the use of screens-having openings of various sizes. To a less extent replacement becomes necessary when a screen has been seriously damagedfrom constant wear or otherwise. Our invention has to do largely with facilitating the easy replacement of screens.

As in other grinders of this type, the screen is in the form of a cylindrical arc and it rests on a plurality oftransverse rods or bars 15. The front and rear end edges of the screen are usually latched; In prior constructions the screen is usually removed through an opening in the side of the casing. The arrangement is cumbersome and difficult to operate andit requires considerable time and laborto remove or insert a'screen. A

furtherdrawback to the old type of screen.

or similar tool.

may then be easily ings for the shaft and, further by the use of very simple clamping devices which operate automatically at the end edges of the screen. In carrying out our invention, we provide the front wall with an opening as best shown in Figure 3. A hinged closure 16 is provided for tightly closing this opening when the rinder is in use. Then the closure 16 is ully closed the forward edge of the screen 14 will rest against the edge of the front wall of the casingat the top of the opening and bearing against the anvil 13. In other words, the screen is clamped at its forward edge between the anvil .13 and the ,closure, 16 with itsupper edge tightly clamped. and

in tangential relation with the front wall. The rear edge of the screen is also tightly clamped between an anvil 18" and the rear wall of the casing. The anvil'13"issecured j to the rear wall by means of a bolt 17 passing through therear wall and through the spacing block 18 and through the anvil 131'.

For facilitating the removal of the screen through the front opening, the rear wall of the casingis provided withan aperture 19 of ample size for introducing'a screw driver The edge of the spacing block is beveled as shown 111 Figure 2 sothat any suitable tool may engage the rearedge of the screen 1 1 for prying the screen loose from its rear connection. This looseningof the screen should be done withthe door 16 open and the movement of the screen 14: will be suflicient to force the forward edge of the screen throughthe opening. The. screen withdrawn through the front opening. i

The clamp for the forward edge of the screen is best shown inFigure 3 taken in connection with Figure 4. The closure 16 is provided with a pivot shaft20, the ends of which are journalled in cars 21 projecting forwardly fromthe side edges of the easing. The middle portion of the upper edge of the closure is cut away as best. shoi'vn in Figure 4. Two substantially L-shaped guides 22 project from the forward edge of the casing, one of their functions being to guide the movements ofthe closure 16. The forwardly projecting portions of the guides 22 are rounded as shown in Figure 3 so that the edge of the closure will ride on the round- 1 ed surfaces of the guides 22. The forward edge of the screen 14: also contacts with the such full. clear, and exact terms that its conguide 22 and it rides into position against the rounded surfaces of the guides 22. It will be apparent from an inspection-of Figure 3 that the closing of theclosure 16 will invlove considerable leverage against the forwardedge of the screen 16 to force it not only intoposition against the anvil 13 but to'also exert a force in the curvilinear directlon along the screen to force the rear end of the screen into the latching position shown in: Figure 2.

'due to the vibration of the machine. have therefore provided a pressure foot for until it is seated against the anvil 13. At

thispoint in the movement the rear edge of the screen is fully latched, and as the forward ed e of the screen leaves the curved surfaces of the guides 22, the resiliency of the screen snaps it into position with the upper edge of the screen contacting with the sectioned edge of the front wall. The closure 16may then be latched by means of the latches 23nand tightened by means of the thumb nuts engaging the latches. The steps are simply reversed when it is desired to remove the screen. The closure 16 is first opened and the forward edge of the screen isthen released so that it bears against the curved surfaces of the guide members 22. A suitable tool is then inserted through the aperture 19 to pry loose the rear edge of the "screen from the rear clamp. This forces the forward edge of the screen forwardly and it may then be removed with very little effort slidable closure 24, Under the vibration of a high speed machine of this character, the

tendency of the closure 24'is to fall and to thus close the opening 12. A fixed pressure againstthe rear of the closure 2a is not adapted for preventing the falling of the closure maintaining a constant ressure against the closure 24: and we have urther added structure for adjusting this pressure. As shown inFigure 1, a collar member 25 is secured to the top wall of the casing and slidable in the collar is a rod 26 having a head 27 the head being preferably made of wood or similar material. The end of the rod 26 carries one or more notches and a coil spring surrounds the rod and extends from the head 27 to the Znuts. It is apparent that the compression of the spring may be varied by tightening or loosening the nuts on the rod 26.

Having thus described our invention in and withdrawal of said screen, and a hinged closure for the opening of said casing, said closure being adapted to exert a leverage action on said screen during the closing movement thereof. I 2. A grinder including a comminutor and a screen within a casing, said casing being provided with an opening for the insertion and withdrawal of said screen, means on said casing for releasably engaging the edge of said screen remote from the opening, and a hinged closure for the opening of said casing, said closure being adapted to exert a leverage action on said screen during the closing movement thereof to force the edge of said screen into engagement with said means. 7 I y 3. A grinder including a comminutor and a screen within a casing, said casing being provided with an opening for the insertion and withdrawal of said screen, and a hinged closure for the opening of said casing, said closure being adapted to exert a leverage action on said screen during the closing movement thereof and having a clamping action I with a portion of said comminutor for engaging an edge portion of said screen therebetween when said closureis in closed posi tion.

4. A grinder including a comminutor and a screen within a casing, said casing being provided with an opening for the insertion and withdrawal of said screen, means on said casing for releasably engagingthe edge of said screen remote from the opening; and a hinged closure for the opening of said casing, 7

said closure being adapted to exert a leverage action on said screen during the closing movement thereof to force the edge of said screen into engagement with said means, said casing being provided with an aperture adjacent said clamping means for the insertion of a pry for releasing said screen from engagement with said means.

5. A grinder including a comminutor and a screen within a casing, said screen having substantially the form of a semicylindrical surface, said casing being provided with an opening adjacent one of the straight edges of said screen for the insertion and withdrawal'of said screen, said screen being movable in the direction of its length, and a closure hingedly secured to said casing and adapted .to close the opening therein, said closure being adapted to exert a leverage action on said screen during the closing movement thereof.

6. A grinder including acomminutor and a screen within a casing, said screen having substantially the form of'a semicylindrical surface, said comminutor includinga pair of anvils secured in spaced away relation to said casing at the end edges of said screen and including also a rotatable beater having its axis of rotation at the cylindrical axis of said screen, said casing being provided with an opening adjacent one of said anvils for the edge portion of said screen clamped therebetween.

In testimony whereof we tures.

CHARLES D. AMMON. ELMER W. .WILCOX.

afiix our signa- 

